Several children were among the missing Thursday after a devastating avalanche buried an Italian mountain hotel with more than 25 people believed to be trapped inside.

The prospects of anyone being rescued alive from the ill-fated Hotel Rigopiano looked bleak with rescue efforts hampered by heavy snow that had blocked access roads to the remote site.

The three-storey building was hit by a two-metre (six-feet) high wall of snow late on Wednesday afternoon.

The first rescue workers only reached the remote site in the early hours of Thursday and it was midday by the time a snow plough and the first mechanical excavation equipment got there.

As some 35 firemen and sniffer dogs combed the rubble, officials said one body had been recovered and the location of another one identified by early afternoon.

"We are trying to recover bodies," said fire service spokesman Luca Cari. Asked if there was any hope of survivors, he told AFP: "You never know."

He added: "The building was basically run over by the avalanche leaving it buried.

"I saw mattresses that had been dragged for hundreds of metres, which shows how big the search area is. There are tonnes of snow, tree trunks and all kinds of detritus."

Italian television showed images of piles of masonry and rubble in the entrance area of what they dubbed a 'coffin hotel'.

- Wife and children missing -

The region was hit by four seismic shocks measuring above five magnitude in the space of four hours on Wednesday, when at least one person was confirmed to have died. Quake experts said the tremors almost certainly triggered the snowslide.

The four-star hotel's guests had been assembled on the ground floor awaiting an evacuation following the quakes that was delayed by snow-blocked roads when the avalanche struck.

The building was moved some 10 metres off its foundations by the force of the hurtling wall of snow.

Local officials confirmed two guests who were not inside when the avalanche struck had been rescued. They were suffering from hypothermia but not in any danger.

One of them, identified as Giampiero Parete, 38, was quoted by friends in Italian media as saying his wife and two children, aged 6 and 8, had been inside the hotel.

Officials said there had been 20 guests staying and seven or eight staff on duty at the hotel on the eastern lower slopes of the Gran Sasso mountain.

The first mountain police on the scene got there by helicopter with others following on skies.

They were quoted as saying there were no signs of life inside the building while one of their commanding officers told reporters: "There are many dead."

Ambulances were blocked for hours by two metres of snow in the nearest village, Farindola, some nine kilometres (5.5 miles) away, according to the civil protection agency.

- Waiting for Godot -

The hotel was located at an altitude of 1,200 metres (3,900 feet) around 90 kilometres (55 miles) east of the epicentres of Wednesday's earthquakes, all near Amatrice, the town devastated in an August quake in which nearly 300 people died.

A region dominated by Gran Sasso, a majestic 2,912 metres (9,554 feet) peak, has numerous small ski resorts popular with day-trippers from Rome and urban centres on Italy's east coast.

The one person confirmed dead Wednesday was a man found buried under the debris of a building in Castel Castagna, a small town to the north of Farindola.

The quakes affected an area that straddles the regions of Lazio, Marche and Abruzzo which is home to many remote mountain hamlets.

Although many residents had been evacuated from their homes after last year's quakes, there were fears for families who had decided to stay and are now cut off.

Guido Castelli, the mayor of the Marche town of Ascoli said his staff were trying to check on around 1,000 people in cut-off hamlets.

"It is like Waiting for Godot," he said.

Some 130,000 homes were without electricity overnight as a result of quake-damage to pylons and other infrastructure.

Schools in the affected region have been closed until next week to allow structural safety checks to be carried out.

Italy is prone to earthquakes but has rarely suffered so many in quick succession.

Since the Amatrice disaster, there have been nine shocks measuring more than a five magnitude and a total of 47,000 registered aftershocks.

Italy straddles the Eurasian and African tectonic plates, making it vulnerable to seismic activity when they move.